1. Field of the Invention
The invention relates to a quick-release skewer for locking one element to another, such as a wheel to a bicycle frame or other object or apparatus.
2. Background Information
Quick-release skewers of the aforementioned type are commonly used to mount and dismount a wheel on a bicycle frame or fork easily and quickly. They are also used in the cycle industry to immobilize the seat post on the seat tube, for example.
Known quick-release skewers for wheels include an elongated rod that extends through the wheel hub, with one end of the rod projecting on each side of the hub. One of the ends of the rod has a first clamping stop that is generally adjustable along the rod. This is usually a threaded end piece or a nut that is screwed onto the threaded end of the rod.
The other end of the rod has a second movable clamping stop, whose movement along the rod is controlled by a lever articulated at the end of the skewer and carrying an eccentric cam. The lever and its cam vary the distance separating the two stops. In particular, they make it possible to tighten simultaneously the two fork mounting brackets between the ends of the hub and the clamping stops.
In the area of the stop, the lever and its eccentric cam generate a movement with an axial component directed along the general direction of the rod.
For safety reasons, safety pins are arranged on the front fork ends (or on the frame tabs). These pins project from the surfaces of the frame or fork which receive the clamping stops. They are arranged such that, to bring the wheel into position, it is necessary to move the stops backward to allow passage above the pins. The height of these pins does not exceed a few millimeters and is slightly greater than the adjustment path generated by the cam. Thus, once the wheel is adequately attached to the bicycle, that is to say, after the lever is closed and an adequate tightening force has been applied, the wheel will not separate completely from the bicycle if the lever were to be opened and, therefore, the quick-release skewer were to become loose. Indeed, the wheel/bike connection will be loose but the wheel will remain in place as the safety pins retain the clamping stops, and therefore the wheel, in place. This loose wheel/bike connection can be sufficient for the cyclist to stop without falling, or at least makes it possible to avoid the most serious falls.
The presence of safety pins increase the number of manipulations required for mounting/dismounting a wheel on a bike. Notably, in addition to the handling of the lever, it is necessary to screw/unscrew at least one of the clamping stops, in general the nut.
Screwing/unscrewing the clamping stops give rise to a plurality of negative consequences in the use of conventional quick-release skewers.
First, it increases the time required for mounting and dismounting the wheel. Added to the increased mounting or dismounting time is a complicated manipulation requiring both hands to operate the quick-release skewer, with one hand on the lever and the other on the nut, thus making it impossible to hold the wheel or the frame.
Furthermore, and perhaps more importantly, it causes the tightening force actually used for mounting the wheel to be inaccurate, thereby making it difficult to reproduce such tightening. Indeed, after loosening the nut and dismounting the wheel, it is difficult to re-tighten the nut with precisely the same number of turns when re-mounting the wheel.
U.S. Pat. No. 5,673,925 discloses a quick-release skewer intended to address some of the problems of conventional devices. In this construction, one of the locking stops, the one that does not include the lever, is provided with an “expandable” ring. In reality, the nut into which the longitudinal rod of the quick-release skewer is screwed includes a T-shaped cap. A collar is inserted between this cap and the front fork end, which includes angular sectors of various lengths. The extensions of the T-shaped cap are in contact with the various angular sectors of the collar, depending upon the angular position of the collar. Thus, it is possible to change the spacing between the two clamping stops without unscrewing the nut.
A device of this type is still not optimal, insofar as it requires two-handed manipulation. Furthermore, the lever and ring of this device are handled completely independently from each other, which may cause errors during manipulation. Indeed, the user can fold the lever irrespective of the position of the ring; however, in order for the tightening to be applied correctly, the ring must be in the correct position prior to folding the lever.